Birth centres are closing, patients are being denied pain-relieving drugs and leaflets advising parents how to prevent cot death have been scrapped because of NHS cuts which are increasingly restricting services to patients, evidence gathered by the Guardian reveals.

The NHS's £20bn savings drive also means new mothers receive fewer visits from health visitors, support for problem drinkers is being reduced and families are no longer being given an NHS advice book on bringing up their baby.

People with diabetes and leg ulcers are seeing less of the district nurses who help them manage their condition; specialists delivering psychological therapies are under threat and a growing number of hospitals are reducing the number of nurses and midwives to balance their books.

The disclosure that the savings drive is affecting so many different areas of NHS care has prompted claims that pledges by the prime minister and the health secretary, Andrew Lansley, that the frontline would be protected despite the NHS's tightening financial squeeze cannot be trusted. One of David Cameron's election pledges was: "I'll cut the deficit, not the NHS."

Inquiries by the Guardian into the impact of the quest to deliver £20bn of "efficiency savings" in the NHS in England by 2015 also shows that walk-in centres are closing and anti-obesity programmes are being scaled back and hospitals reducing the number of nurses and midwives they employ, despite rising demand for healthcare and an ongoing baby boom.

Katherine Murphy, chief executive of the Patients Association, said: "Andrew Lansley promised the NHS cuts to save the £20bn would be in bureaucracy and waste and would not come at the expense of the frontline. But the evidence we are getting on a daily basis is that the impact is on the patient and frontline services."

"Ministerial promises aren't being kept. We are getting the complete opposite of what we were promised. We were promised no cuts to frontline services and no impact on the patient's journey. Instead we are getting cuts in many, many services and the impact on the patient is huge."

Patients denied painkillers such as co-codamol and tramadol and the sleeping tablet diazepam have contacted the association recently to complain that prescriptions have suddenly been withdrawn.

One of the NHS's 10 regional strategic health authorities has banned primary care trusts (PCTs) in its area from prescribing patients a range of painkillers on cost grounds, Murphy added. Patients on oxygen due to breathing problems have seen visits from district nurses reduced, while other patients have been denied cataract, bariatric or hernia operations, she added.

Children's health experts are dismayed that parents will no longer automatically receive Birth to Five, a longstanding guide to issues such as feeding and immunisation, because the Department of Health has decided to make it an online-only publication as part of a DH purge on health promotion material. Dr David Elliman, a spokesman for the Royal College of Paediatrics and Child Health, said: "If Birth to Five is no longer to be available to mothers in print, only on the internet, this is bad news. I am particularly concerned that those who profit from it most will be least likely to use it. This is a false economy and is likely to increase inequalities. We would urge DH to think again."

The Foundation for the Study of Infant Deaths also warned that switching Reduce the Risk – a leaflet that gives parents advice on avoiding cot death – to an online-only format would deprive parents, especially those from low income and disadvantaged backgrounds, of potentially vital guidance, as many are unlikely to download it. Research credits the leaflet with helping to avoid 19,000 cot deaths since it was first published in 1991.

Jacque Gerrard, director for England at the Royal College of Midwives, said shutting birth centres such as the Jubilee, in Hull, and Heatherwood, in Ascot, where midwives rather than doctors supervise women's care, would deny mothers-to-be their right to choice of place of birth. At least six more reconfigurations of maternity services, which could result in further closures, are being discussed by the NHS.

Campaigners for sick babies have warned that a reduction in the number of nurses at a third of neonatal units in English hospitals could result in deaths. "The lives of England's sickest babies are at risk by needless cuts to the neonatal nursing workforce," said Andy Cole, the chief executive of the baby charity Bliss.

Bliss used freedom of information laws to investigate staffing levels in neonatal units. Despite the charity identifying a shortfall of 1,150 nurses in those units last year, some 140 posts have been lost since then through redundancies, recruitment freezes and redefining some staff roles. One in five units also said that they intend to reduce their total of neonatal nurses in the next 12 months.

Ipswich hospital confimed that it plans to shed 250 staff as part of a drive to reduce its 3,800-strong full and part-time workforce in order to help it confront "a serious and urgent financial challenge" and make £16m of efficiency savings during this financial year. Those being made redundant by the end of the year include both clinical staff and non-medical support staff. It is shrinking its workforce despite emergency and elective care admissions having risen in the last three years.

The cash squeeze affecting the hospital is so acute that it has no plans to replace a specialist nurse who retired last week who helped about 50 patients suffering from multiple sclerosis manage their conditions. "The MS nurse specialist post is under review. We do however have a serious and urgent financial challenge to face and are going through a period of consultation on a number of posts," said a hospital spokeswoman.

The spokeswoman said the £16m target was the result of NHS organisations in England having to make 4% efficiency savings this year towards the £20bn goal and the service's Quality, Innovation, Productivity and Prevention (QIPP), which also wants healthcare providers to become more efficient in order to free up resources to cope with the demands of an increasingly elderly population.

Christina McAnea, head of health at Unison, the union representing 400,000 NHS staff including nurses and paramedics, said the emerging cuts were "a shocking indictment" of the government. The public will not be fooled by David Cameron's hollow words ever again.

"Just over a year in office, and the damage to the NHS is clear to see: birth centres closing, patients left in pain, public health programmes dwindling, district nurse visits being cut, health workers losing their jobs. Waiting lists are rising, and the health bill no-one wants will change our health service beyond recognition, throwing the doors open to privatisation on a never before seen scale," she said.

Janet Davies, director of nursing at the Royal College of Nursing, warned that cuts made in the next three years may be more painful for staff and patients than those in this financial year. "While the cuts we are currently seeing are fairly worrying, we have even more concern about the future, because the task to cut costs and make savings will only get harder. Some trusts have managed to make savings this year in a sensible way that hasn't directly affected patient care. But next year the increased pressure, because the NHS has to make three more years of savings for the three years after this, it's harder to identify where innovation and reduction in waste can make savings.

Sir Bruce Keogh, the NHS medical director, said hospitals and PCTs should not be using the £20bn efficiency drive to cut services to patients. "There is no need for NHS organisations to cut services that their local population requires. The NHS will receive an extra £12.5bn over the next four years and in future we want it to focus more on designing services around patients.

"Even with this significant increase in funding, the growing pressures of an ageing population and the rising costs of drugs and other treatments means that the NHS still needs to save up to £20bn by 2015. This is not about cuts – it is about becoming more efficient, so that even more money can be spent on providing high quality care for patients, not less.

"We are clear that there should be no blanket bans for treatments, that the NHS must be sensitive to individual circumstances and have systems in place for exceptional cases so individuals can get the most appropriate treatment for them."